I. Field of the invention
The invention relates to a nozzle for welding, heating, cutting and/or flame cleaning, comprising a cutting oxygen duct and with an internal mixing device, arranged in the nozzle head, for heating gas and heating oxygen and with metering channels possibly arranged around the centrally placed oxygen duct, for heating gas and heating oxygen.
II. Description of the Prior Art
In the case of copper alloy nozzles in accordance with the prior art for the heating, necessary in the case of flame cutting operations, of the material to be cut and in the case of welding operations, the heating gas and the oxygen are passed unmixed before ignition into the nozzle body and are so introduced into it that they supply a hot even flame or several individual flames. As a matter of principle for the operations under discussion three different heating systems are employed:
(1) The heating system with post-mixture in which the heating gas and heating oxygen are supplied in the nozzle and are only mixed after emergence from the nozzle;
(2) THE INJECTOR HEATING SYSTEM IN WHICH THE HEATING GAS AND THE HEATING OXYGEN ARE MIXED IN OR AT THE NOZZLE DUE TO THE HEATING GAS ENTRAINING THE HEATING OXYGEN OR VICE VERSA DUE TO THE INJECTOR-LIKE CONSTRUCTION OF THE NOZZLE; AND
(3) THE HEATING SYSTEM WITH MULTIPLE INTERNAL MIXING IN WHICH DUE TO THE CONSTRUCTION OF A LARGE NUMBER OF SMALL INJECTOR DUCTS WITH MIXING ZONES ON THE NOZZLE CROSS-SECTION A LARGE NUMBER OF SMALL HEATING FLAMES ARE FORMED.
The nozzles mentioned in paragraph (1) above when suitably constructed prevent flashback and backfire. They are relatively insensitive to pressure changes and can also be produced economically. Their disadvantage resides in that the mixing of the two heating media is incomplete and this gives rise to a lesser heating efficiency and to a relatively high gas consumption. The nozzles mentioned in paragraph (2) above can also be economically produced. They produce a better mixing action and therefore a better heating efficiency than nozzles of the first group. They can, however, flashback and backfire and are very sensitive to changes in pressure or adjustment of pressure. As a result their construction and efficiency is limited. The nozzles described in paragraph (3) above can be made as reliably as the nozzles of the first group. The gas oxygen utilization is optimum and the heating flames have a high temperature. However, they have the disadvantage that their production is relatively expensive because the heating flames must be projected in a concentrated manner. The construction of such ducts is very difficult to carry out. Furthermore, in the case of cutting and flame cleaning nozzles of this type the encasing of the oxygen jet is not optimum so that the impingement surface of the heating flames is excessively large. There are also difficulties with regard to setting and pressure differences in nozzles of this type.